Johnson, who leads major league pinch hitters with a .355 batting average and a .444 on-base percentage, is the third Atlanta outfielder currently on the DL.
Braves manager Fredi Gonzalez said Tuesday that center fielder B.J. Upton, sidelined by a right hip strain, is expected to begin a rehab assignment with Triple-A Gwinnett on Wednesday. Reserve outfielder Jordan Schafer, out with a bruised right ankle, could begin with Gwinnett as early as Saturday.
Atlanta purchased the contract of Todd Cunningham from Gwinnett to take Johnson's spot on the 25-man roster.
Cunningham hit .279 with 18 stolen bases in 19 games at Gwinnett.